To Estimate Relative Bioavailability of 5 Formulations of Ronacaleret Given to Healthy Postmenopausal Females

An Open-label, Randomized, Five Period Crossover Study to Estimate the Relative Bioavailability of Five Formulations of 400 mg Ronacaleret (a Calcium-sensing Receptor Antagonist) Administered as a Single Oral Dose to Healthy Postmenopausal Females.

This study will examine the effects of formulation on the relative bioavailability of SB-751689 (400 mg) administered to healthy postmenopausal women. Subjects will receive a single oral dose of each formulation, with five formulations of SB-751689 tested in total. Blood samples will be taken up to 24 hours postdose after each dose administration. This study will provide information for future possible formulation development of SB-751689 for Phase III.

Inclusion criteria:

• Healthy postmenopausal women
• Non-smokers
• Body weight > or = 50 kg and BMI within the range 19-32 kg/m2
• Capable of giving written informed consent and complying with the requirements and restrictions listed in the consent form
• QTcB or QTcF < 450 msec; or QTc < 480 msec in subjects with Bundle Branch Block
• Hispanic or non-Hispanic (Caucasian) ethnicity

Exclusion criteria:

• Any clinically relevant biological or physical abnormality found or reported at screening which, in the opinion of the investigator, is clinically significant and would preclude safe participation in this study
• Positive urine drug screen at screening
• Positive urine test for alcohol at pre-dose
• Positive for HIV or hepatitis B or C virus at screening
• Urinary cotinine levels indicative of smoking at screening
• History of smoking or use of nicotine containing products within one year of the study or >10 pack-year history of smoking overall
• History of regular alcohol consumption exceeding 7 units/week (1 unit = 5 ounces of wine or 12 ounces of beer or 1.5 ounces of hard liquor) within 6 months of screening
• History of drug abuse within 6 months of the study
• Participation in a clinical study and received a drug or a new chemical entity with 30 days or 5 half-lives, or twice the duration of the biological effect of any drug (whichever is longer) prior to the first dose of the current study medication.
• Exposure to more than four new chemical entities within 12 months prior to the first dosing day.
• Use of prescription or non-prescription drugs
• Consumption of red wine, grapefruit, grapefruit juice or grapefruit containing products within 14 days prior to the first dose of study medication
• Donation of blood in excess of 500 mL within 56 days prior to dosing
• Evidence of renal, hepatic or biliary impairment
• History of serious gastrointestinal disease
• History of sensitivity to any of the study medications or components thereof or a history of drug or other allergy that, in the opinion of the physician responsible, contraindicates their participation.
• History of clinically significant cardiovascular disease
• Medical conditions that might alter bone metabolism
• Serum parathyroid hormone (iPTH) test levels outside the reference range at screening
• Liver function tests, parathyroid hormone test or CPK outside the reference range at screening